Modulation of long-term potentiation-like cortical plasticity in the healthy brain with low frequency-pulsed electromagnetic fields

Abstract

Background: Non-depolarizing magnetic fields, like low frequency-pulsed electromagnetic fields (LF-PEMFs) have shown the ability to modulate living structures, principally by influencing synaptic activity and ion channels on cellular membranes. Recently, the CTU Mega 20 device was presented as a molecular accelerator, using energy up to 200J and providing high-power (2 Tesla) pulsating fields with a water-repulsive (diamagnetic) action and tissue biostimulation. We tested the hypothesis that LF-PEMFs could modulate long-term corticospinal excitability in healthy brains by applying CTU Mega 20 ® . Ten healthy subjects without known neurological and/or psychiatric diseases entered the study. A randomized double-blind sham-controlled crossover design was employed, recording TMS parameters (amplitude variation of the motor evoked potential as index of cortical excitability perturbations of the motor system) before (pre) and after (post +0, +15, +30min) a single CTU Mega 20 session on the corresponding primary right-hand motor area, using a real (magnetic field=2 Tesla; intensity=90J; impulse frequency=7Hz; duration=15min) or sham device. A two-way repeated measures ANOVA with TIME (pre, post +0, +15, +30min) and TREATMENT (real vs. sham stimulation) as within-subjects factor was applied. Results: A significant TIME×TREATMENT interaction was found (p<0.001). Post hoc comparisons showed a significant effect of TIME, with significant differences at +0, +15 and +30min compared to baseline after real stimulation (all p<0.05) but not after sham stimulation (all p<0.05) and significant effects of TREATMENT, with significant differences at +0, +15 and +30min for real stimulation compared to sham stimulation (all p<0.005). No significant depolarizing effects were detected throughout the (real) stimulation. Conclusions: Our proof-of-concept study in healthy subjects supports the idea that non-ionizing LF-PEMFs induced by the CTU Mega 20 diamagnetic acceleration system could represent a new approach for brain neuromodulation. Further studies to optimize protocol parameters for different neurological and psychiatric conditions are warranted.